Process of dyeing with vat dyes



Patented Sept. 1941 PROCESS OF DYEING WITH VAT DYES ,Jean G. Kern, EastAurora, N. Y., assignor to National Aniline & Chemical Company, Inc.,New York, N. Y., a corporation of New York No Drawing. ApplicationNovember 28, 1938,

Serial No. 242,744

11 Claims.

This invention relates to the art of dyeing and particularly to the artof dyeing cellulosic textile fibers, such as cotton or regeneratedcellulose fibers in the form 01 yarns or piece goods, with vat dyes.

As is well known, the vat dyes are insoluble in water in the unreducedform, but upon reduction with a reducing agent, such as sodiumhydrosulfite, they are converted to leuco forms which are soluble to acertain extent in alkaline solutions. In dyeing with these dyes, theprocedures used involve either first forming an alkaline solution orsuspension of a leuco vat dye, contacting the material to be dyed withthe solution or sus-v pension, and then oxidizing the dye in the fabric,

or applying the unreduced vat dye to the material, subsequently passingthe impregnated material through an alkaline solution containing areducing agent whereby the dye in the material is converted to the leucoform and penetrates the material, and then oxidizing the dye.

At the present time, piece goods are generally dyed with vat dyes in anyone of three methods involving the use of the above procedures. In thefirst two methods, a jigger and a padding machine are used,respectively. They are similar in that a non-acid solution or suspensionof a leuco vat dye is employed, the piece goods being brought intocontact with the solution or suspension so as to impregnate the materialwith the relatively soluble leuco vat dye. The dyeing is then completedby oxidizing the leuco dye in the goods, as by passing .the goodsthrough an oxidizing bath, and finishing in the usual manner. Inthethird method for dyeing piece goods with vat dyes, the goods arepadded with a padding liquor containing an unreduced vat dye, water, anda thickener, and are then passed through an alkaline bath ofhydrosulfite wherein the unreduced dye is converted tothe leuco form inthe presence of the goods. The dyeing of the piece goods 7 is completedin a manner, in general, simil r to that employed in dyeing piece goodsin a re uced solution. Raw stock and spun cotton are generally dyed indyeing machines in which these ma-- terials are brought into contactwith a non-acid solution or suspension of a leuco vat dye- Dyeing ofyarns is accomplished in a similar manner except that the solution orsuspension of the leuco vat dye is passed through the yarns disposed onperforated beams or the like.

The reduced bath which is required in most of the above-describedprocesses is ordinarily made by passing a water mix of the vat dyestuffinch) to form an aqueous paste, diluting the paste' somewhat with water,and addingit to a dye bath containing a corresponding amount of alkaliand a reducing agent such as sodium hydrosulfite. The dyeing is carriedout by first raising the temperature of the dye bath to a suitable pointaccording to the particular dyestuiT used and, when complete reductionof the dyestufi is effected, starting the dyeing operation. It isimportant in order to secure satisfactory results that during the dyeingoperation the dye be kept in as complete solution or dispersion aspossible. Although the theoretical considerations uponwhich the processof dyeing with vat dyes is based are not clearly understood, it is knownthat results, which are evidenced by the brilliancy',penetratiomiastness, and yield in the process, are'better as the I leucovat dyes are more finely divided and more nearly in true solution,

In order to obtain a solution or fine dispersion of the leucoyat dyes inthe dye bath, it is important first that the dyestuff as added to thedye bath be very finely divided. To this end the dyestufi, prior tobeing introduced into the dye bath, is converted to a finely-dividedform and is ordinarily employed in the form of a paste prepared asdescribed above by screening-a mixture of the dyestuff and water. Pastesof this type may contain, in addition, dispersing agents and/or othersuitable ingredients. The dyestufi may also be supplied in the form of apowder containing the finely-divided vat dyestufl. and materials whichassist in making the powder readily dispersible in water. Even with theuse of the dyestuff pastes and powders at present in commercial use,some color value is often lost because the fiber does not absorb all ofthe dye present in the bath. This is due to the fact that part of thedye is not' in a suitable adsorbable form. The unused'and thereforewasted dvestui! in many cases adheres loosely to the surface of thefibers and is washed ofi. readily during the soaping operation whichfollows the dyeing. Also, in many cases the production of even dyelngshas been prevented because of the excessive afiinity of the reduceddyestufl for the fiber, some portions of the fiber being dyed morereadily than other portions.

It'is an object of the invention to provide a process for dyeing withvat dyes which is characterized by producing dyeings of excellentpenetration, brilliancy, and levelness.

Another object of the invention is to provide a through a fine screen(e. g.,.200 mesh per square process of dyeing with vat dyes in which thevat dyes are substantially completely exhausted from the dye bath, andexcellent yields are obtained.

Another object of the invention is to provide a valuable process ofdyeing with vat dyes with which satisfactory results ordinarily are notobtained when using commercial processes.

A further object of the invention is to provide dyeing liquorscontaining vat dyes, which liquors may be employed in the production ofvaluable dyeings.

Other. objects of the invention will in part be obvious and will in partappear hereinafter.

The present invention is based upon the discovery that certainhydroxylated aliphatic polyamines, which are identified more fullyhereinafter, possess a combination of properties which make themvaluable additions to dye baths for the dyeing of textile fibers,particularly natural and artificial cellulosic fibers, with vat dyes.Thus, it has been found that by mixin one or more of these hydroxylatedaliphatic polyamines with a finely-divided vat dye and water and thenintroducing the resulting mixture into an aqueous solution containingcorresponding amounts of alkali and a reducing agent such as sodiumhydrosulfite, a dye bath consisting of a true solution of the leuco vatdye is obtained which produces excellent results when used in dyeingtextile fibers. Similarly, it has been found that the hydroxylatedaliphatic polyamines can be incorporated with advantage in a paddingliquor containing an unreduced vat dye. In this case,

- they assist in producing an effective dispersion of the insoluble dyein the padding liquor and increase the solubility of the leuco vat dyeformed when the material impregnated with the padding liquor is passedthrough the jigger containing the alkaline solution of the reducingagent. The latter effect may also be obtained by adding the polyaminesto the alkaline reducing solution in the jigger.

The hydroxylated aliphatic polyamines which are adapted for use in theprocess and compositions of the present invention are aliphatic aminocompounds containing a plurality of amino groups and at least onehydroxyl group. The central aliphatic radical of the polyamines may be achain or cyclic alkyl radical. The amino groups of these polyamines maybe unsubstituted or may contain alkyl radicals or aralkyl radicals assubstituents. As employed in this specification and claims the termalkyl radicals" denotes and includes chain and cyclic alkyl radicals.The hydroxyl group or groups of the compounds may be in the centralaliphatic radical thereof or may be in an N-alkyl radical or radicals.Where the central aliphatic radical is free from hydroxyl groups atleast one and preferably two or more of the substituents of the aminogroups are hydroxyalkyl radicals containingla maximum of three hydroxylgroups.

Thus the polyamines which may be used in the vat dye compositions may berepresented by the following general formula:

wherein R. represents an alkyl radical (which radical may be an openchain or cyclic alkyl radical and may be unsubstituted or may containsubstituents which do not alter the essential characteristics of thecompound, such as, for example, hydroxyl, alkoxy, and aralkyloxy groups,etc.) X1, X2, X1, and X4 each represents hydrogen, an alkyl'radical, anaralkyl radical. a hydroxyalkyl radical containing a maximum of threehydroxyl groups, or a. part of a cyclic radical including R, and atleast one and preferably two or more of the substituents represented byX1, X2, X3, and X4 being a hydroxyalkyl radical of this class when theradical represented by R. is free from hydroxyl groups; and n representsa small whole number. It will be understood that the aralkylsubstituents of the amino groups of the compounds may themselves containsubstituents, especially hydroxyl groups in the alkyl groups thereof.Where the alkyl group of an aralkyl radical is two carbon atoms inlength or longer and contains hydroxyl groups, it is regarded as ahydroxyalkyl radical for the purposes of this invention.

1,2-di-(2-ethanol-amino-) ethane HOCHzCHzNH-CHaCHz-NHCHzCI-HOH 1,2-bis-(di-2' -ethan ol-amino) ethane (HOCHzCHz) eNCH2CH2-N(CH2CH2OH) 2 1,2-di- 2 ,3 -propan-diol-amino-) ethane on I on di-(N-butyl-N-ethanolamino-) ethane C(Hl CAH NCHzCH:N

HOCHaCH: CHzCHzOH 1,3-di-(2'-ethano1amino-)-2-propano1HOCHzCHzNH-CHzCHOHCHz-NHCH2CH2OH 1,3-bis- (di-2'-ethanolamino-)-2-propanol tri- (mono-methyl-amino-methy1-) ethanol CHINHCH;

cnmncm-o 011,011

OHaNHCH: tri (di-methyl-amino-methyl-) ethanol (one aNCH:

( a)2NCH2-C CHzOH (CH3) 2N CH2 l-para-hydroxy-benzyl-amino 2 di-(hydroxyethy1amino-) ethane HOOCHzNH-CHzCHz-N(CH1CHzOH)z 1,2-di-(4'-cyclohexanol-amino-) ethane 1,2-di-(N hydroxycyclohexyl Nethylamino-) ethane 1100,1110 oinl'oon N-CHzCHz-N H5O: CzHt l-parahydroxybenzylamino- 2 hydroxyethyl amino-ethane HoOonmn-cmom-rmombmon1,2-di (N cyclohexyl-N-hydroxy-ethylamino-) 1 ethane CaHu CoHu'\NCH:CH2' noomon; 011,011,011 N,'N' diethanol diethylenediamine,otherwise known as 1.4-diethanolpiperazine CH:OH2 nocnzcnm NCHzCIhOEiCHa-C a N,N di (propandiol 2,3)-diethylenediamine, I

otherwise known as l.4-di(propandiol-2,3)- piperazine The lower carbonchain compounds of the above type have low melting points, and areviscous liquids at ordinary temperatures; the viscosity of the compoundsincreasing with increase methods; for example, they may be obtained bythe action of alkylene oxides upon: an aliphatic diar'nine as disclosedby Knorr, Ber. vol. 35, page 4471, or by condensation of monoordialkylolamines with the poly halohydrins of poly alcohols.

where the process involves the use of a non-acid solution of a leuco vatdye, one or more of the hydroxylated aliphatic polyamines abovedescribed can be added as such to the dye bath, the dyestuffbeing'separately added. However, it is usually preferred to mix thepolyamines with a vat dyestufi paste comprising essentially a relativelyfinely-divided unreduced vat dye and water. The resulting mixture isthen diluted somewhat with water to. form a suspension which is passedthrough a screen of the type referred to above. A highly dispersedsuspension of the unreduced vat dye is obtained as a result of thistreatment and the suspension is added to the dye bath containing thealkali and the reducing agent; The temperature of the dye bath is thenbrought to the appropriate dyeing temperature required at the beginningof the dyeing operation. By prothe dyeing of piece goods in a jigger orpadding device or it may be used for the dyeing of raw stock, spuncotton, or yarn in the machines which ordinarily. takes about 45minutes, the

material is rinsed and treated with an oxidizing agent such as sodiumbichromate or sodium perborate, rinsed, thoroughly soaped, again rinsed,

allowed to dry, and finished according to the usual methods.

In dyeing textile fibers in accordance with the present invention usingthe pad and jig process, one or more of the above-described hydroxylatedaliphatic polyamines can be used in the padding liquor or in thedevelopment bath, or both. It is usually preferable to use thepolyamines in the padding liquor and in this case the unreduced vatdyestuff is mixed with one or more of the hydroxylated aliphaticpolyamines and to the resulting mixture water, a gum, and an oil, suchas bleaching oil, are added to form a padding liquor having a desiredconcentration of the ingredients. The material to be dyed is then paddedwith the padding liquor, dried, and later developed on a jigger in asolution containing The process of the present invention can be 0 thealkali and reducing agent in the'manner above described. Additionaldyestufi may of course be added in the jigger if necessary.

Instead of preparing ,a mixture for incorporation withthe otheringredients of a vat or padding liquor as described above, there may beemployed for the preparation of these dyeing solutions or suspensions avat dyestuif paste prepared as described in my application Serial No.242,742, filed of even date herewith, and containing one or a mixture ofthe hydroxylated aliphatic polyamines. Further, in place 'of the vatdyestufi pastes referred to above, there may be used vat dye powderc'ompositio'ns' as described in my United States Patents Nos. 2,067,926and 2,074,150, in which case the dyestuff powders are first impastedwith water and the resulting vat dye pastes are then used in thesamemanner as the pastes of finely-divided vat dye and wa-- ter referred toabove.

Although it will be understood that the invention is not limited to anytheoretical explanation, Y it appears that the advantages resulting fromthe use of the hydroxylated aliphatic polyaminesin the present processare at least partly due to the fact that the polyamines are capable offorming amine salts with leuco vat dyes which salts are relativelysoluble in alkaline solutions as compared with the alkali salts of theleuco vat dyes. Thus, as above pointed out, while in the normal vat aportion at least of the leuco vat dye is in the form of a suspensionrather than a true solution, by adding a proportion of a hydroxylatedaliphatic polyamine of the above class to the vat, the portion of theleuco vat dye in dispersed form is rendered substantially completelysoluble. This result is probably in part due to the fact that the abovehydroxylated aliphatic polyamines are relatively strongly basic, thisproperty making them capable of forming amine salts with the leuco vatdyes. In this way, the hydroxylated aliphatic polyamines aredistinguished from the alkylolmonoamines which have been suggested foruse in vat dyeing processes, the beneficial effect of thealkylolmonoamines being evidenced only in the cases of certain dyes ofthe indanthrene series. The increase in the solubility of leuco vat dyesby use of the hydroxylated aliphatic polyamines also appears to be dueto the fact that these amines are relatively soluble in water and thecombination of a leuco vat dye and a hydroxylated aliphatic polyamineconsists substantially of a leuco vat dye containing awater-solubilizing group.

Whatever the explanation, it has been found that the use of thehydroxylated aliphatic polyamine involves several important advantages.

- Thus,'the exhaust of vat dye baths containing the rate of absorptionof the dyes by the fiber,

thereby equalizing the depth of dyeing and giving deeply penetrated andlevel results. The penetration is apparently due to the wetting andpenetrating power of the polyamines for the fabric. This action isespecially important when dyeing with highly chlorinated blues of theindanthrene type, such as Carbanthrene Blue BCS (Color Index No. 1114).

Due to the excellent penetration and fixation of the dyestuif on thematerial, on soaping the material in a boiling soap solution, thedyestufi remains on the fiber which thus retains the full color value ofthe penetrated dyestufi'. An important application of the process of thepresent invention is in the dyeing of shirting material using theindanthrene blues. In this case, it is of utmost importance to obtainshades which do not change in cast on repeated washings'with soap. Byusing the present process in dyeing shirting material with the variousindanthrene blues, vivid and red-cast shades are obtained at the end ofthe dyeing process, which shades are stable and do not change onrepeated soapings. Examples of indanthrene blues are the following:Carbanthrene Blue GCD (C I. No. 1113) and Carbanthrene Blue BCS (C. I.No. 1114) As pointed out above, the hydroxylated aliphatic polyaminesemployed in the present process are preferably incorporated in thedyeing compositions by mixing them with the dyestufl paste prior'toadding the paste to the dye bath. This is of advantage since thepolyamines assist in insuring a well-dispersed condition of thedyestufi, thus expediting the screening operation which ordinarilyprecedes the incorporation of the dyestufi paste into the dye bath. Thisproperty of the polyamines is particularly valuable when the pad and jigdyeing process is used since substantially speck-free suspensions may beobtained which are adapted to be uniformly applied to a material. Thepresent process is especially well adapted for the tinting and dyeing ofspun goods in a reduced bath in a continuous manner. Because of thesolubilizing power of the hydroxylated aliphatic polyamines, the leucovat dyes are substantially completely soluble and penetrate rapidly intothe fibers when applied by means of a three-roller padding machine.

In order that the invention may be more fully understood, referenceshould be had to the following examples which illustrate typicalprocesses coming within the scope of the invention. It will beunderstood, of course, that these examples are given for illustrativepurposes merely and are not intended as limitations of the invention.

Example 1.-An 8 /2 per cent shade of Carbanthrene Blue GCD (C. I. No.1113) on 150 pounds of mercerized cotton piece goods is obtained in thefollowing manner. of Carbanthrene Blue GCD paste are mixed with 6 poundsof 1,2-di-(2-ethanol-amino-)ethane. To the resulting mixture 1 gallon ofcold water is added and the suspension thus formed is passed through afine screen. A speck-free paste is obtained which is added to ajiggerdye bath containing 10 pounds of caustic soda, 15 pounds of sodiumhydrosulfite (concentrated10 pounds being added immediately and theremaining 5 pounds after one passage), and 100 gallons of water. Thetemperature is raised to 110 F. and after complete reduction the dyeingis started at this temperature. The temperature is then allowed to riseto 125 F; over a period of 30 minutes and the dyeing operation iscarried on at this temperature for about 15 minutes. The goods are thengiven one wash, four passages in an aqueous solution containing 2 /2pounds of sodium perborate per 100 gallons at a temperature of 120 F.,two cold washes, and five passages in a boiling soap solution containing3 pounds of soap per 100 gallons. The goods are thereafter rinsed andwashed in the open, dried, and finished in the usual manner.

Exampie 2.In this example an 8 /2 per cent shade of Carbanthrene BlueGCD is obtained on 150 pounds of mercerized cotton piece goods using avat dyestufi paste prepared by mixing 400 parts by weight of a presscake of Carbanthrene Blue GCD (containing 70 per cent water and 30 percent solids as dry vat dye) with a smooth paste composed of l00 parts ofwater and 500 parts of 1,2-di-(2-ethanol-amino-)ethane. 12.75 pounds ofthis vat dye color paste are screened and introduced into a bathconsisting of 100 gallons bulk and containing 10 pounds of caustic soda(dry) and 15 pounds of sodium hydrosulfite. The dyeing process in thisbath is carried out as described in Example 1.

Example 3.This example offers an illustration of the application of thepresent invention to the dyeing of the piece goods by the pad and mixing5 pounds of this vat dyestuffpaste, 11V;

gallons of water, 8 ounces of gum tragacanth,

12.75 pounds I and pounds of bleaching oil, the whole making up 12 /2gallons bulk. This padding liquor is then used for padding cottonshirting cloth, the pressure of the pad roller being so regulated as toleave 60 per cent of moisture in the padded cloth. The padded materialis then dried and developed in a jigger containing a developing bathprepared in .the same manner as the dye bath of Example 2 prior to theaddition of the vat dyestufl paste of that example, an additionalquantity of the above vat dyestufi past being added to the solution inthe jigger so as to produce an 8 /2 per cent dyeing. The oxidation andfinishing of the. material are carried out in the I usual manner.

GCD, 11 gallons ofwater, 8 ounces of gum tragacanth, and 5 pounds ofbleaching oil to make up a total of 12 gallons bulk. The developmentbath is th same as that described in Example 3 except that a' quantityof 2-hydroxy- 1,3-di(hydroxyethylamino)propane equal to the amount ofthe dyestufi is added. The dyeing is carried out in the same manner asin Example 3. In place of the Carbanthrene Blue GCD of this example,there may be employed an equal amount of Carbanthrene Dark Blue DR (C.I. No. 1099) or Carbanthrene Violet 2R (C. I. No. 1104).

Example 5.This is an example of the application of the invention in thedyeing of yarns in packages so as to produce a 5 per cent shade ofCarbanthrene Dark Blu DR. The percentages referred to below are basedupon the weight of yarn to be dyed. The dyeing liquor is made up bymixing 5 per cent of the ordinary vat color paste of the above dye, 2per cent of caustic soda (dry), 3 per cent of sodium hydrosulfite, and 3per cent of1,2-bis-(di-2-ethanol-amino) ethane with enough water'toinsure proper circulation, the amount of water'depending upon the sizeand model of the machine used. The conditions of dyeing are the same asare usually employed in dyeing yarns in packages with vat dyes. Afterdyeing, th yarn is rinsed, oxidized with approximately 2 per cent ofsodium perborate, rinsed, soaped, rinsed, and dried.

If desired, this example may be varied by using a vat dyestufi pastealready containing a hydroxylated aliphatic polyamine in place of thevat dyestuiI paste used above. In this case the addition of ahydroxylated aliphatic polyamine as such to the dye bath may bedispensed with. The Carbanthrene Dark Blue DR of the above example maybe replaced with other vat dyes; e. g., excellent results may beobtained using Carbanthrene Violet 2R.

As previously indicated, the foregoing examples are merely illustrativeof a few of the ways in which the present invention may be practiced.Hence, the procedures herein described may be varied widely within thescope of the invention. Thus, in place of the hydroxylated aliphaticpolyamines used in the processes described in the examples, there may beemployed one or a mixture of the hydroxylated aliphatic polyamines ofthe above class; e. g., there may be employed any one or a mixture ofthose specifically mentioned above. While the results obtained inparticular cases willvary depending upon the specific polyamine used, inusing any of the above class, the advantages'herein pointed out can beobtained. With respect to the amount of hydroxylated aliphatic polyaminerequired to produce these advantages, .it will be recognized that thiswill be dependent upon the dyestuff employed, the material to be dyed,and the specific dyeing procedure used. In this connection it is to benoted that the aliphatic polyamines not only act to increase thesolubility of leuco vat dyes, but also appear to act upon textile fibersto increase their ability to absorb the dyes. In general, there shouldbe employed an amount of hydroxylated aliphatic polyamine about equalto. the amount of dystufi employed and ordinarily the amount ofhydroxylated aliphatic polyamine should not be reduced below aboutone-half part by weight for each part by weight .of the dyestufl.Although an excess of a polyamine ordinarily does not have a criticaleifect upon the operativeness of the process, the use of an excess isundesirable for economic reasons.

The process of the invention, in general, may be employed with advantagefor dyeing with any vat dyestufi. Among suitable vat dyestufls may bementioned the following:

- Color Index No. Carbanthrene Yellow G paste 1118 Carbanthrene GoldenOrange 2RT paste 1097 Carbanthrene Golden Orange G double paste 1096Carbanthrene Blue Green FFB double paste 1173 Carbanthrene Violet 2Rpaste 1104 Carbanthrene Dark Blue DR paste 1099 Carbanthrene Flavine GCdouble powder 1095 Carbanthrene Red Violet'ZRNX paste 1161 CarbanthreneBrilliant Green supra 1101 Brilliant Indigo 4G 1189 wherein R representsan alkyl radical; X1, X2, X3, and X4 each represents a member selectedfrom the group consisting of hydrogen, alkyl radicals, an ethyleneradical formed by X1 and X3 together when R is an ethylene radical and nis 1, aralkyl radicals, and hydroxyalkyl radicals containing a maximumof three hydroxyl groups, at least one of the substituents representedby X1, X2, X1, and X4 being a hydroxyalkyl radical of said class whenthe radical represented by R. is free from hydroxyl groups; and nrepresents a whole number not greater than 2. I

2. The process of dyeing textile fibers with vat dyes which comprisescontacting the fibers with a bathcomprising a non-acid solution of aleuco vat dye and a hydroxylated aliphatic diamine containing at leastone N-hydroxyalkyl group,

said diamine being free from hydroxalkyl groups containing more thanthree hydroxyl groups and free from N-substituents other than alkylgroups, aralkyl groups and their hydroxy derivatives.

" 3. In the dyeing of textile fibers with vat dyes by the pad and jigprocess in which the fibers are impregnated with a padding liquorcomprising a suspension of an unreduced vat dye and are then passedthrough a developing bath comprising an alkaline reducing solution, theimprovement which comprises incorporating in the padding liquor ahydroxylated aliphatic diamine containing at least one N-hydroxyalkylgroup, said diamine being free from hydroxyalkyl groups containing morethan three hydroxyl groups and free from N-substituents other than alkylgroups, aralkyl groups and their hydroxy derivatives.

4. In the dyeing of textile fibers with vat dyes by the pad and jigprocess in which the fibers are impregnated with a padding liquorcomprising a suspension of an unreduced vat dye and are then passedthrough a developing bath comprising an alkaline reducing solution, theimprovement which comprises incorporating in the developing bath ahydroxylated aliphatic diamine containing at least one N-hydroxyalkylgroup, said diamine being free from hydroxyalkyl groups containing morethan three hydroxyl groups and free from N-substituents other than alkylgroups, aralkyl groups and their hydroxy derivatives.

5. In the dyeing of textile fibers with vat dyes from a dye bath, theimprovement which comprises carrying out the dyeing with the aid of ahydroxyalkylated alkylene diamine containingat least one N-hydroxyalkylgroup, said diamine being free from hydroxyalkyl groups containing morethan three hydroxyl groups and from N- substituents other than alkylgroups, aralkyl groups and their hydroxy derivatives.

6. A vat dye bath comprising an alkaline aqueous solution of a leuco vatdye and a hydroxylated aliphatic polyamine of the following generalformula:

wherein R represents an alkyl radical; X1, X2, 11;,

and X4 each represents a member selected from said class when theradical represented by R is free from hydroxyl groups; and n representsa whole number not greater than 2.

7. A padding liquor for dyeing with vat dyes comprising an aqueoussuspension of an unreduced vat dye, a thickener, and a hydroxylatedaliphatic polyamine of the following general wherein R represents analkyl radical; X1, X2,

. n is 1, aralkyl radicals, and hydroxy-alkyl radicals containing amaximum of three hydroxyl groups, at least one of the substituentsrepresented by X1, 1%, X3, and X4 being a hydroxyalkyl radical of saidclass when the radical represented by R is free from hydroxyl groups;and n represents a whole number not greater than 2.

8. A developing bath for developing unreduced vat dyes on piece goodscomprising an aqueous solution containing caustic soda, sodium hydrosulfite, and a hydroxylated aliphatic polyamine of the following generalformula:

wherein R represents an alkyl radical; X1, X2,

IQ, and X4 each represents a member selected from the group consistingof hydrogen; alkyl radicals, an ethylene radical formed by X1 and X2together when R is an ethylene radical and n is 1, aralkyl radicals, andhydroxyalkyl radicals containing a maximum of three hydroxyl groups, atleast one of the substituents represented by X1, X2, X3, and X4 being ahydroxyalkyl radical of said class when the radical represented by R isfree from hydroxyl groups; and 11. represents a whole number not greaterthan 2.

9. In the dyeing of textile fibers with vat dyes from a dye bath, theimprovement which comprises carrying out the dyeing with the aid of 2-hydroxy- L ,,3-di (hydroxyethylamino) propane.

10. In the dyeing of textile fibers with vat dyes from a dye bath, theimprovement which comprises carrying out the dyeing with the aid of 1,4-di (propandio1-2,3) -piperazine.

11. In the dyeing of textile fibers with vat dyes from a dye bath, theimprovement which comprises carrying out the dyeing with the aid of1,2-di(4 cyclohexanol-amino-) ethane.

JEAN G. KERN.

